ᐅ Should interior window sills be installed before or after the interior plaster?

We would like to have interior window sills made of natural stone installed. Normally, window sills are measured after the windows are installed and then fitted before the interior plastering is done.

Unfortunately, the window sills have a very long delivery time, but the date for the interior plastering cannot be postponed.

I am hesitant to measure the window sills before the windows are in because I think there is too much that could go wrong.

What is the difference if I install the window sills after the interior plastering is already done? Is that possible? I have read that the appearance is different—can someone explain this to me?

Snowy36 schrieb:
I’m reluctant to measure the window sills before the windows are installed because I think too many things could go wrong.

Hmm, yes, this reminds me of a thread like this one: https://www.hausbau-forum.de/threads/fensterbaenke-innen-welche-tiefe-bzw-ueberstand.26609/
Try using the search function a bit; questions about window sills and interior plastering are quite common topics here.

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11ant schrieb:
Uh, yeah, this makes me think of this thread: https://www.hausbau-forum.de/threads/fensterbaenke-innen-welche-tiefe-bzw-ueberstand.26609/
Try searching a bit with the search function; questions about window sills and interior plastering are quite common here.

Thank you for your reply. I have now read through the entire thread, but unfortunately it doesn’t answer my question, so I will try to clarify it better...

Our site manager prefers to install the window sills on the inside before plastering. This would look nicer but also causes the scheduling issues mentioned above because the window sills have such long delivery times.

My question is: if you plaster first and then install the window sills, what visual differences would there be on the window sills?

I was told that when the window sill is installed after the interior plastering, some of the plaster on the left and right sides needs to be chiseled away... Okay, I understand that because otherwise the window sill wouldn’t fit. This also means that the plasterer will have to come back to do some finishing work once the window sills are installed...?!

But wouldn’t it look the same on the left and right, plastered around the sill, as if I installed them before plastering?

Snowy36 schrieb:
My question was, if you plaster first and then install the window sills, what visual differences can be seen on the window sills?

A cropped image from our future kitchen might help illustrate the difference. The window sill on the right window was properly plastered in place, including inside the window recess. The left window has no window sill because the countertop will eventually extend all the way to the window. If you wanted to install a window sill there afterward, the plaster in the lower part of the window recess would have to be removed again to fit the sill in from the side and then replastered. Alternatively, you can leave a section without plaster during the initial plastering. Both options, however, require time-consuming rework. That’s why the rule is: always install window sills before plastering.

Best regards

Axel

AxelH. schrieb:
A photo of a section of our future kitchen might help illustrate the difference. The right window has the windowsill properly plastered in place, including inside the window recess. At the left window, the windowsill is missing because the countertop will later extend all the way up to the window. If you wanted to install a windowsill there afterwards, you’d have to remove the plaster from the lower part of the window recess again so it can be fitted from the side and then replastered. Alternatively, you leave out a piece of plaster when plastering. Both options mean time-consuming rework. That’s why the rule is: always install windowsills before plastering.

Best regards

Axel

Thanks, Axel, this is exactly what I was looking for...

So, it’s just too time-consuming to do the rework afterwards, which is why you do it beforehand....

Unfortunately, I’ll have to wait 3–4 weeks for the windowsills. If I only measure the dimensions after the windows are installed plus the 4 weeks production time, and then the plasterer can come, my project will be delayed not only by that time but also additional waiting time because the plasterer might not be available exactly when I need him... I’m looking for a solution for this...

Measuring windowsills before the windows are installed is nonsense, right?